Surgical instruments incorporating inflatable membranes or balloons, commonly referred to as balloon catheter instruments, have a wide variety of applications including use in, for example, angioplasty devices for clearing an occluded or blocked artery, urethral sphincters, tissue expanders or dilators, etc. One type of balloon catheter incorporates a plunger disposed within a syringe housing. The plunger is axially advanceable within the syringe housing in response to pressure directly applied to the rear end of the plunger to dispense the inflation fluid within the balloon. Another type of balloon catheter includes a plunger which is rotatably mounted within the syringe housing. The plunger distally translates in response to rotation thereof to dispense the inflation fluid into the balloon. Examples of conventional balloon catheters are described in U.S. Pat. Nos. 4,832,692; 5,084,060; 5,147,300; and 5,284,480. Such devices are typically operated by trained health care providers, such as physicians, physician's assistants, paramedics, nurses, etc., for therapeutic intervention. For the purpose of the present application, these people are collectively referred to as operators.
Although conventional balloon catheters such as those described above and disclosed in the aforementioned patents have proven to be generally effective in certain applications, these devices suffer from a number of disadvantages which detract from their usefulness. In particular, one disadvantage of conventional balloon catheters is that such devices require a two handed operation, i.e., one hand creates the force necessary to move the plunger within the syringe housing while the other hand is used to hold and stabilize the catheter. As a consequence, the operator is incapable of performing any other dexterous maneuver during the application of the catheter. Other disadvantages of conventional balloon catheters include the inability to incrementally and selectively control the amount of fluid pressure supplied to the inflatable member, the insufficiency in providing structure to rapidly inflate or deflate the inflatable member, and the relative complexity of the operating components.
A device operable with one hand permits the free hand to be used for other functions. For example, in a percutaneous tracheostomy procedure, a device requiring both hands would not allow an operator to use one hand continuously to stabilize and position the anterior neck and trachea to provide a stable insertion site.
U.S. Pat. No. 5,147,300 to Robinson et al. describes a balloon catheter instrument which attempts to address some of the aforementioned shortcomings of conventional instruments. The Robinson '300 instrument includes a housing, a syringe body and a handle. A threaded plunger is attached to the handle and advances within the syringe body in response to rotation of the handle. The instrument further includes a half nut mechanism which is selectively engageable with the threaded plunger. When the half nut mechanism is in engaged relation with the threaded plunger, the plunger is advanced by rotation of the handle. In the disengaged position of the half nut mechanism, the plunger may be advanced by depressing the handle without any rotational movement.
There are certain disadvantages inherent in the design of the Robinson '300 instrument. For example, similar to the afore-described balloon catheter devices, the Robinson '300 instrument requires a two handed operation; one hand to hold the instrument and the other hand to rotate the handle to advance the plunger. The half nut mechanism, although providing a means for rapidly inflating or deflating the balloon, is relatively complex thereby increasing cost of the instrument and decreasing the economic feasibility of disposing the instrument after a minimal number of uses, or even single use.
The present invention is especially useful for the percutaneous (i.e. through skin) placement of a tracheostomy tube, which is a plastic tubular elongated airway that facilitates respiratory exchange via a hole in front of the neck. Modern tracheostomy tubes typically incorporate an inflatable cuff at the end of the tube to provide support and protection.
A standard open surgical tracheostomy, also commonly referred to as tracheostomy, is a procedure to make a surgical opening through the superior aspect of the neck and into the trachea, usually between the first and second tracheal cartilages. Open tracheostomy is a time consuming, expensive and sometimes dangerous procedure usually performed in an operating room. It usually involves extensive tissue dissection and retraction, plus special lighting and equipment. Cricothyroidotomy is a high morbidity, emergency surgical procedure performed higher in the neck for the placement of a tracheostomy tube. Over 80,000 tracheostomies are performed each year in the United States. At the time of the tracheostomy procedure, most patients already have artificial airway tubes in place through the nose or mouth; less than 5% of all tracheostomies are emergency procedures.
Several percutaneous tracheostomy procedures have been developed to allow the procedure to be conducted at the patient's bedside. The most common approach uses a series of progressively larger diameter mechanical dilators passed over a guide wire. The implementation of the serial dilators requires use of both hands. Thus, the operator does not have a free hand, useful, for example, to stabilize the neck. Contemporary percutaneous progressive mechanical dilation techniques are slow, awkward and often dangerous.
Better percutaneous tracheostomy equipment and techniques are needed.